Hyrodgen partial pressure control in a vacuum process chamber

ABSTRACT

Implementations described herein generally relate to methods for removing one or more processing by-products found in deposition systems, such as in vacuum forelines of vapor deposition systems. More specifically, implementations of the present disclosure relate to methods of reducing the buildup of hydrogen in systems. In one implementation, a method of processing a substrate in a deposition chamber is provided. The method comprises depositing a layer on the substrate, wherein hydrogen-containing by-products are produced in a vacuum foreline fluidly coupled with the deposition chamber during the depositing process. The method further comprises flowing an oxidizing agent gas into the vacuum foreline to react with at least a portion of the hydrogen-containing by-products in the foreline.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of co-pending U.S. patent applicationSer. No. 15/806,600, filed Nov. 8, 2017, which claims benefit of U.S.Provisional Patent Application Ser. No. 62/421,609, filed Nov. 14, 2016,which is incorporated herein by reference in its entirety.

BACKGROUND Field

Implementations described herein generally relate to methods forremoving one or more processing by-products found in deposition systems,such as in vacuum forelines of vapor deposition systems. Morespecifically, implementations of the present disclosure relate tomethods of reducing hydrogen incorporation into deposited films due tohydrogen buildup in the processing chamber during a deposition process.

Description of the Related Art

In some deposition applications, film quality is inversely related tothe amount of hydrogen incorporated in the deposited film. The amount ofhydrogen incorporated in the deposited film is a strong function of thepartial pressure of hydrogen at the surface of the growing layer ordeposited layer formed in a deposition chamber. Several common metal anddielectric deposition processes use hydrogen-containing precursors(e.g., SiH₄, Si₂H₆, Si₃H₈, trisilylamine, TEOS, etc.). When thesehydrogen-containing precursors react in the deposition chamber, a largeamount of hydrogen is released as a by-product of the reaction.Traditional mechanical vacuum pumps rely on moving and static parts tocreate and maintain a pressure differential across and through the pumpsunder gas load conditions. These vacuum pumps are typically poor atpumping lighter weight atoms and molecules, such as hydrogen as the gapsbetween the rotating impeller and casing are too large to trap and movehydrogen further downstream from the processing chamber and aretherefore inefficient. This inability to pump hydrogen leads to anincreased partial pressure of hydrogen in the processing region of thedeposition chamber. As many substrates within a batch are sequentiallyprocessed within the deposition chamber, the amount of hydrogenincorporated into the films formed on each sequentially processedsubstrate also increases.

Thus, there is a need for improved methods and systems for removinggases that are hard to pump, such as hydrogen, from a processing regionof a deposition chamber within a deposition system.

SUMMARY

Implementations described herein generally relate to methods forremoving one or more processing by-products found in deposition systems,such as in vacuum forelines of vapor deposition systems. Morespecifically, implementations of the present disclosure relate tomethods of reducing the buildup of hydrogen in systems. In oneimplementation, a method of processing a substrate is provided. Themethod comprises flowing a reactive gas into a vacuum forelinecontaining a hydrogen-containing by-product. The method furthercomprises reacting the reactive gas with at least a portion of thehydrogen-containing by-product in the vacuum foreline to form a reactionproduct. The reaction product contains a molecule that has a molecularmass greater than a molecular mass of the hydrogen-containingby-product. The method further comprises pumping the reaction productout of the vacuum foreline.

In another implementation, a method of processing a substrate isprovided. The method comprises depositing a layer on a substratedisposed in a processing volume of a deposition chamber.Hydrogen-containing by-products are formed within the processing volumeduring the depositing a layer. The method further comprises evacuatingthe processing volume using a vacuum pump fluidly coupled to theprocessing volume by a vacuum foreline. The evacuating the processingvolume delivers the hydrogen-containing by-products into the vacuumforeline. The method further comprises flowing a reactive gas into thevacuum foreline. The reactive gas and at least a portion of thehydrogen-containing by-products react in the vacuum foreline to form areaction product comprising a molecule having a molecular mass higherthan a molecular mass of the hydrogen-containing by-products.

In another implementation, a system for processing a substrate isprovided. The system comprises a deposition chamber, a vacuum forelinethat connects a vacuum pump to the deposition chamber, a reactionchamber fluidly coupled with and positioned along the vacuum foreline inbetween the vacuum pump and the deposition chamber, a valve to controlflow between the deposition chamber and the vacuum foreline, and areactive gas supply system. The reactive gas supply system comprises atleast one reactive gas source, an inlet line that fluidly couples the atleast one reactive gas source to the vacuum foreline, and at least onevalve connected to the inlet line to control the flow of the reactivegas from the at least one reactive gas source into the vacuum foreline.

In another implementation, a method of processing a substrate in adeposition chamber is provided. The method comprises depositing a layeron the substrate, wherein hydrogen-containing by-products are producedin a vacuum foreline fluidly coupled with the deposition chamber duringthe depositing process. The method further comprises flowing anoxidizing agent gas into the vacuum foreline to react with at least aportion of the hydrogen-containing by-products in the foreline.

In another implementation, a method of processing a substrate that isdisposed in a processing volume of a deposition chamber is provided. Themethod comprises depositing a layer on the substrate that is disposed inthe processing volume, wherein hydrogen-containing by-products areformed within the processing volume during the process of depositing thelayer, evacuating the processing volume while depositing the layer onthe substrate using a vacuum pump that is fluidly coupled to theprocessing volume by a vacuum foreline, wherein evacuating theprocessing volume causes the hydrogen-containing by-products to migrateinto the vacuum foreline and flowing a reactive gas into the vacuumforeline to react with at least a portion of the hydrogen-containingby-products in the foreline, wherein the reaction between the reactivegas and the hydrogen-containing by-products forms a molecule that has ahigh molecular mass than the hydrogen-containing by-product.

In yet another implementation, a system for processing a substrate isprovided. The system comprises a deposition chamber for depositing alayer, a vacuum foreline that fluidly couples a vacuum pump to thedeposition chamber, a reaction chamber fluidly coupled with andpositioned along the vacuum foreline in between the vacuum pump and thedeposition chamber, a valve to control flow between the depositionchamber and the vacuum foreline, and an oxidizing agent-containing gassupply system. The oxidizing agent-containing gas supply systemcomprises at least one oxidizing agent-containing gas source, an inletline that fluidly couples the at least one oxidizing agent-containinggas source to the vacuum foreline, and at least one valve connected tothe inlet line to control the flow of at least one oxidizingagent-containing gas from the at least one oxygen-containing gas sourceinto the vacuum foreline. The oxidizing agent-containing gas is adaptedto react with processing by-products in the reaction chamber.

In yet another implementation, a system for processing a substrate isprovided. The system comprises a deposition chamber, a vacuum forelinethat connects a vacuum pump to the deposition chamber, a plasma sourcefluidly coupled with and positioned along the vacuum foreline in betweenthe vacuum pump and the deposition chamber, a valve to control flowbetween the deposition chamber and the vacuum foreline, and a reactivegas supply system. The reactive gas supply system comprises at least onereactive gas source, an inlet line that fluidly couples the at least onereactive gas source to the vacuum foreline, and at least one valveconnected to the inlet line to control the flow of the reactive gas fromthe at least one reactive gas source into the vacuum foreline. Adistance between the deposition chamber and the plasma source is between0 meters and 3 meters.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description ofthe implementations, briefly summarized above, may be had by referenceto implementations, some of which are illustrated in the appendeddrawings. It is to be noted, however, that the appended drawingsillustrate only typical implementations of this disclosure and aretherefore not to be considered limiting of its scope, for the disclosuremay admit to other equally effective implementations.

FIG. 1A is a simplified schematic diagram representing one exemplaryimplementation of a pumping system according to implementations of thepresent disclosure;

FIG. 1B is another simplified schematic diagram representing oneexemplary implementation of a pumping system according toimplementations of the present disclosure;

FIG. 2 is a schematic cross-sectional view of a substrate processingsystem incorporating the pumping system of FIG. 1A, according toimplementations of the present disclosure; and

FIG. 3 is a process flow diagram of a method for removing hydrogen gasfrom a foreline, according to one or more implementations describedherein.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of oneimplementation may be beneficially incorporated in other implementationswithout further recitation.

DETAILED DESCRIPTION

The following disclosure describes systems for removing hydrogen fromdeposition systems. Certain details are set forth in the followingdescription and in FIGS. 1A-3 to provide a thorough understanding ofvarious implementations of the disclosure. Other details describingwell-known structures and systems often associated with depositionsystems and pumping systems are not set forth in the followingdisclosure to avoid unnecessarily obscuring the description of thevarious implementations.

Many of the details, dimensions, angles and other features shown in theFigures are merely illustrative of particular implementations.Accordingly, other implementations can have other details, components,dimensions, angles and features without departing from the spirit orscope of the present disclosure. In addition, further implementations ofthe disclosure can be practiced without several of the details describedbelow.

Implementations described herein will be described below in reference toa deposition process that can be carried out using any suitable thinfilm deposition system. Examples of suitable systems include theCENTURA® systems which may use a DxZ™ processing chamber, PRECISION5000® systems, PRODUCER™ systems, PRODUCER GT™ and the PRODUCER SE™processing chambers which are commercially available from AppliedMaterials, Inc., of Santa Clara, Calif. Other tools capable ofperforming deposition processes may also be adapted to benefit from theimplementations described herein. In addition, any system enabling thedeposition processes described herein can be used to advantage. Theapparatus description described herein is illustrative and should not beconstrued or interpreted as limiting the scope of the implementationsdescribed herein.

For pressures below 100 Torr, where most CVD processes are performed, ahydrogen partial pressure gradient is established along a pumping flowpath 205 (FIG. 2). The pumping flow path 205 generally includes a pathalong which gases flow from the processing volume 226 (FIG. 1A) to thepumping system 100 and out the exhaust 131 (e.g., scrubber or vent)through the vacuum foreline 120. This hydrogen partial pressure gradientis governed by mass transport due to the interaction with other heaviergases in the reaction (in laminar flow regime) and/or diffusion.Diffusion generally becomes more significant at lower pressures where amolecular flow regime is significant. In some implementations of thepresent disclosure, a larger concentration gradient is created along thepumping flow path by reacting free hydrogen with an oxidizing agentdownstream of a deposition chamber to form a heavier by-product that canmore easily pumped out by use of a conventional pumping system, such asvacuum pump 130. This heavier by-product (e.g., higher molecular mass)can be more easily pumped away by conventional mechanical vacuum pumps(e.g., roots blower, turbo pump, etc.), ion pumps, cryopumps andgetters. In some implementations, free hydrogen is reacted with anoxidizing agent in the vacuum foreline 120. In another implementation,free hydrogen is reacted with the oxidizing agent in a reactor (e.g.,reaction chamber 160 in FIG. 1A). The reactor can be positioned inlinealong the vacuum foreline 120 or on a bypass. In one implementation, atleast one of the reactants (e.g., free hydrogen and oxidizing agent) isexposed to an energy source (e.g., ultraviolet (“UV”) source, remote RFplasma, capacitively coupled plasma, inductively coupled plasma,transformer coupled plasma (TCP), microwave, thermal energy, etc.) toenergize the reactant to form the heavier by-products. In someimplementations, the reactant(s) are energized while in the reactor. Inanother implementation, the reactant(s) are energized prior to enteringthe reactor and/or vacuum foreline.

FIG. 1A is a simplified schematic diagram representing one exemplaryimplementation of a pumping system 100 according to implementations ofthe present disclosure. The pumping system 100 is fluidly coupled with adeposition chamber 110 via a vacuum foreline 120. The deposition chamber110 is generally configured to perform at least one integrated circuitmanufacturing process, such as a deposition process, an etch process, aplasma treatment process, a preclean process, an ion implant process, orother integrated circuit manufacturing process. The deposition chamber110 may be a vacuum-assisted deposition chamber. The process performedin the deposition chamber 110 may be plasma assisted. For example, theprocess performed in the deposition chamber 110 may be plasma depositionprocess for depositing a silicon-based material.

The vacuum foreline 120 is fluidly coupled with the vacuum pump 130. Areactive agent-containing source 140 for supplying a reactive agent(e.g., O₂, O₃, N₂O, N₂O₂, or NF₃) is fluidly coupled with the vacuumforeline 120. In one implementation, the reactive agent-containingsource 140 is fluidly coupled with the vacuum foreline 120 via areactive agent inlet supply line 150. In one implementation, thereactive agent inlet supply line 150 supplies the oxidizing agentdirectly to the vacuum foreline 120. In another implementation, thepumping system 100 further includes a reaction chamber 160 for reactingthe one or more processing by-products produced by the depositionchamber 110 with the oxidizing agent. In the implementation depicted inFIG. 1A, the reaction chamber 160 is positioned in-line with the vacuumforeline 120 and fluidly coupled with the reactive agent-containingsource 140. In another implementation, the reaction chamber 160 ispositioned on a bypass fluidly coupled with the vacuum foreline 120. Inone implementation an energy source 180 a, 180 b (collectively 180)(e.g., UV source, remote RF plasma source, capacitively coupled plasma,inductively coupled plasma, microwave, thermal energy, etc.) is used toenhance the efficiency of the reaction of the reactive materials (e.g.,hydrogen-containing by-products and/or oxidizing agent) for energizingat least one of the reactant(s) that is provided to the reaction chamber160. The energy source 180 may be positioned at other locations withinthe pumping system 100. For example, in one implementation, the energysource 180 a is coupled with the reactive agent-containing source 140.In another implementation, the energy source 180 is positioned along thereactive agent inlet supply line 150. In another implementation, theenergy source 180 b is coupled with the reaction chamber 160. In yetanother implementation, as depicted in FIG. 1B, the energy source 180 ispositioned in-line with the vacuum foreline 120. In yet anotherimplementation, the energy source is directly coupled with thedeposition chamber 110.

In some implementations, where the energy source 180 is a plasma source,the plasma source may be disposed downstream of the deposition chamber110. The plasma generated in the plasma source energizes and/ordissociates, partially or fully, the compounds within the effluentcoming out of the deposition chamber 110, converting the compounds inthe effluent into more benign form.

In one implementation, as illustrated in FIG. 1A, conversion of the oneor more processing by-products, such as hydrogen-containing gases (e.g.,atomic hydrogen, hydrogen ions, hydrogen radicals, etc.), is performedby delivering the oxidizing agent from the reactive agent inlet supplyline 150. The reactive agent inlet supply line 150 is connected to thevacuum foreline 120, which is connected to the deposition chamber 110(e.g., deposition chamber 110 in FIG. 2). In general, the one or moreprocessing by-products may include gas molecules, partially reactedprecursor materials, un-reacted vapor phase compounds, partially reactedparticulate material and/or other reaction by-products. The reactiveagent inlet supply line 150 may be connected at one end to the vacuumforeline 120 and at the other end to the reactive agent-containingsource 140, which may be adapted to deliver pure oxygen (O₂) gas, ozone(O₃), nitrous oxide (N₂O), dinitrogen dioxide (N₂O₂), nitrogentrifluroide (NF₃), or combinations thereof. The reactiveagent-containing source 140 may alternately or additionally be adaptedto deliver other non-oxygen containing gases, such as nitrogen (N₂),that are configured to reduce hydrogen to form a hydrogen-containingby-product (e.g., ammonia (NH₃)) that has a greater molecular mass. Thereactive agent inlet supply line 150 and vacuum foreline 120 may join ata location on vacuum foreline 120 upstream of the vacuum pump 130. In analternative implementation, the oxidizing agent, or other non-oxygencontaining gases, can be ionized or oxygen radicals can be formed by useof the energy source 180 (e.g., UV source, remote RF plasma source) toenhance the efficiency of the reaction of the reactive materials (e.g.,hydrogen-containing by-products) in the vacuum foreline 120 and thereactive agent-containing source 140.

In one implementation, a chamber foreline valve 124 is placed at asection of the foreline just downstream of where the vacuum foreline 120connects to the deposition chamber 110 and upstream of where the vacuumforeline 120 and the reactive agent inlet supply line 150 meet (e.g.,reaction chamber 160, if present). The chamber foreline valve 124 isable to control the amount of fluid communication between the depositionchamber 110 and the vacuum foreline 120, and prevent any oxidizingagents, hydrogen, oxygen or other materials from entering andcontaminating the deposition chamber 110 from the vacuum foreline 120.The chamber foreline valve 124 may be a throttle valve that isconfigured to control the gas flow rate in the vacuum foreline 120and/or pressure within the processing volume 226 of the depositionchamber 110. In one implementation, a valve 154, which may include apneumatic valve, mass flow controller (MFC) and/or needle valve, is usedto control the flow of gases within the reactive agent inlet supply line150. The pressure of the gases entering the vacuum foreline 120 from thereactive agent-containing source 140 should be high enough so that thereactive gases have an opportunity to react with the hydrogen-containinggases, but not so high as to overwhelm the vacuum pump 130. In oneimplementation, a mass flow controller can be used instead of a needlevalve for valve 154. The valve 154 could be controlled to turn on theoxygen flow for a brief period after each deposition cycle.

During an oxidizing agent purge cycle, the chamber foreline valve 124 isgenerally closed to prevent reaction or contamination within thechamber. Once the chamber foreline valve 124 is closed, a vacuum willremain in the portion of the vacuum foreline 120 downstream of thechamber foreline valve 124 and any gas present in the vacuum foreline120 will evenly distribute throughout the volume available in the vacuumforeline 120. In one implementation, the oxidizing agent reacts with thehydrogen-containing by-products in the vacuum foreline 120 that areformed during each deposition cycle performed in the deposition chamber110. The oxidizing agent reacts with and converts thehydrogen-containing by-products to a heavier by-product that can bepumped away by the vacuum pump 130.

In one implementation, the oxidizing agent purge process is performedbetween deposition cycles. It should be noted that in otherimplementations, the oxidizing agent purge process is run during adeposition cycle, while the deposition chamber 110 is in operation, toreact with hydrogen-containing by-products formed during the depositioncycle. In such implementations, a negative pressure should be maintainedin the vacuum foreline 120 downstream of the reactive agent inlet supplyline 150 so that the flow of oxidizing agent-containing gas does notenter and contaminate the deposition chamber 110. The flow of oxidizingagent-containing gas should not be so high as to overwhelm the vacuumpump 130 downstream.

In one implementation, an oxidizing agent (e.g., N₂O) is fed into thereactor and energized to nitrogen radicals (N*) and oxygen radicals(O*). The radicals then react with hydrogen in the pumping path to formheavier gases (e.g., NH₃ and H₂O) which are pumped away. The consumptionof hydrogen in the reaction creates a hydrogen concentration gradientfrom the deposition chamber to the reactor creating a “pull” or“diffusive movement” of hydrogen away from the deposition chamber andtowards the vacuum pump 130. From the reactor to the vacuum pump,conventional pumping properties apply, as the by-products (e.g., NH₃ andH₂O) are heavier gases. At the lower vacuum pressures in the vacuumforeline 120 the movement of hydrogen towards the vacuum pump 130 by agas flow or viscous drag mechanism is not very effective and thus themovement of hydrogen in the vacuum foreline 120 is largely affected by adiffusion process, whose “flow” rate is governed by the magnitude of theconcentration gradient.

FIG. 1B is another simplified schematic diagram representing oneexemplary implementation of another pumping system 190 according toimplementations of the present disclosure. The pumping system 190 issimilar to the pumping system 100 except that energy source 180 ispositioned directly in-line with the vacuum foreline 120. The depositionchamber 110 has a chamber exhaust coupled by the vacuum foreline 120 tothe energy source 180. In one implementation, the energy source 180 is aplasma source. The exhaust of the energy source 180 is coupled by anexhaust conduit 194 to pumps and facility exhaust, schematicallyindicated by a single reference numeral 196 in FIG. 1B. The pumps aregenerally utilized to evacuate the deposition chamber 110, while thefacility exhaust generally includes scrubbers or other exhaust cleaningapparatus for preparing the effluent of the deposition chamber 110 toenter the atmosphere.

The energy source 180 is utilized to perform an abatement process ongases and/or other materials exiting the deposition chamber 110 so thatsuch gases and/or other materials may be converted into a moreenvironmentally and/or process equipment friendly composition.

In some implementations, the reactive agent-containing source 140 iscoupled to at least one of the vacuum foreline 120 and gases and/or theenergy source 180. The reactive agent-containing source 140 provides anabatement reagent into the energy source 180, which may be energized toreact with or otherwise assist converting the materials to be exitingthe deposition chamber 110 into a more environmentally and/or processequipment friendly composition.

Optionally, a pressure regulating module 198 may be coupled to at leastone of the energy source 180 or exhaust conduit 194. The pressureregulating module 198 injects a pressure regulating gas, such as Ar, N,or other suitable gas, which allows the pressure within the energysource 180 to be better controlled, and thereby provide more efficientabatement performance.

In one implementation, the vacuum foreline 120 is not present and theenergy source 180 is coupled directly to the deposition chamber 110. Adistance between the deposition chamber and the in-line energy source isrepresented by “x.” In one implementation, the distance “x” is betweenabout 0 feet (0 meters) and about 15 feet (about 4.6 meters). In oneimplementation, the distance “x” is between about 1 foot (0.3 meters)and about 15 feet (about 4.6 meters). In one implementation, thedistance “x” is between about 0 feet (0 meters) and about 10 feet (about3 meters). In another implementation, the distance “x” is between about1 foot (0.3 meters) and about 10 feet (about 3 meters). In anotherimplementation, the distance “x” is between about 1 foot (about 0.3meters) and about 5 feet (about 1.5 meters). In another implementation,the distance “x” is between about 5 feet (about 1.5 meters) and about 10feet (about 3 meters).

FIG. 2 is a schematic cross-sectional view of a substrate processingsystem 232 incorporating the pumping system 100 of FIG. 1A, according toimplementations of the present disclosure. Although not depicted, thepumping system 100 depicted in FIG. 2 may be replaced by the pumpingsystem 190. The substrate processing system 232 includes the depositionchamber 110 coupled to a gas panel 230, a controller 210, and pumpingsystem 100. The deposition chamber 110 generally includes a top wall224, a sidewall 201 and a bottom wall 222 that define a processingvolume 226. A support pedestal 250 is provided in the processing volume226 of the deposition chamber 110. The support pedestal 250 is supportedby a stem 260 and may be typically fabricated from aluminum, ceramic,and other suitable materials. The support pedestal 250 may be moved in avertical direction inside the deposition chamber 110 using adisplacement mechanism (not shown).

The support pedestal 250 may include a heater element 270 suitable forcontrolling the temperature of a substrate 290 supported on a surface292 of the support pedestal 250. In one implementation, the heaterelement 270 is embedded in the support pedestal 250. The supportpedestal 250 may be resistively heated by applying an electric currentfrom a power supply 206 to the heater element 270. The heater element270 may be made of a nickel-chromium wire encapsulated in anickel-iron-chromium alloy (e.g., INCOLOY®) sheath tube. The electriccurrent supplied from the power supply 206 is regulated by thecontroller 210 to control the heat generated by the heater element 270,thus maintaining the substrate 290 and the support pedestal 250 at asubstantially constant temperature during film deposition. The suppliedelectric current may be adjusted to selectively control the temperatureof the support pedestal 250 between about 100 degrees Celsius to about700 degrees Celsius.

A temperature sensor 272, such as a thermocouple, may be embedded in thesupport pedestal 250 to monitor the temperature of the support pedestal250 in a conventional manner. The measured temperature is used by thecontroller 210 to control the power supplied to the heater element 270to maintain the substrate 290 at a desired temperature.

The pumping system 100 is coupled to a port formed in the bottom wall222 of the deposition chamber 110. The pumping system 100 is used tomaintain a desired gas pressure in the deposition chamber 110. Asdescribed herein, the pumping system 100 also evacuates post-processinggases and by-products of the process from the deposition chamber 110.

The substrate processing system 232 may further include additionalequipment for controlling the chamber pressure, for example, valves(e.g. throttle valves and isolation valves) positioned between thedeposition chamber 110 and the pumping system 100 to control the chamberpressure.

The substrate processing system 232 may further include a purge gassource 204 for supplying a purge gas to the processing volume 226.

A showerhead 220 having a plurality of apertures 228 is disposed on thetop of the deposition chamber 110 above the support pedestal 250. Theapertures 228 of the showerhead 220 are utilized to introduce processgases into the deposition chamber 110. The apertures 228 may havedifferent sizes, number, distributions, shape, design, and diameters tofacilitate the flow of the various process gases for different processrequirements. The showerhead 220 is connected to the gas panel 230 thatallows various gases to supply to the processing volume 226 duringprocess. Plasma is formed from the process gas mixture exiting theshowerhead 220 to enhance thermal decomposition of the process gasesresulting in the deposition of material on a surface 291 of thesubstrate 290.

The showerhead 220 and the support pedestal 250 may form a pair ofspaced apart electrodes in the processing volume 226. One or more RFpower sources 240 provide a bias potential through a matching network238 to the showerhead 220 to facilitate generation of plasma between theshowerhead 220 and the support pedestal 250. Alternatively, the RF powersources 240 and matching network 238 may be coupled to the showerhead220, support pedestal 250, or coupled to both the showerhead 220 and thesupport pedestal 250, or coupled to an antenna (not shown) disposedexterior to the deposition chamber 110. In one implementation, the RFpower sources 240 may provide between about 100 Watts and about 3,000Watts at a frequency of about 50 kHz to about 13.6 MHz. In anotherimplementation, the RF power sources 240 may provide between about 500Watts and about 1,800 Watts at a frequency of about 50 kHz to about 13.6MHz. Alternatively, plasma is supplied to the processing volume 226 viaa remote plasma source 252.

The controller 210 includes a central processing unit (CPU) 212, amemory 216, and a support circuit 214 utilized to control the processsequence and regulate the gas flows from the gas panel 230. The CPU 212may be of any form of a general-purpose computer processor that may beused in an industrial setting. The software routines can be stored inthe memory 216, such as random access memory, read only memory, floppy,or hard disk drive, or other form of digital storage. The supportcircuit 214 is conventionally coupled to the CPU 212 and may includecache, clock circuits, input/output systems, power supplies, and thelike. Bi-directional communications between the controller 210 and thevarious components of the substrate processing system 232 are handledthrough numerous signal cables collectively referred to as signal buses218, some of which are illustrated in FIG. 2.

Deposition Process Example

FIG. 3 is a process flow diagram of a method 300 for removing hydrogengas from a foreline, according to one or more implementations describedherein. The method 300 may be performed using the pumping system 100,the pumping system 190, and/or the deposition chamber 110.

At operation 310, a layer is deposited on a substrate in a processingvolume of a processing chamber. Hydrogen-containing by-products aretypically formed during deposition of the layer. In someimplementations, the hydrogen-containing by-products are formed in theprocessing volume of the deposition chamber, a vacuum foreline fluidlycoupled with the processing volume, or both the processing volume andthe vacuum foreline. In some implementations, the hydrogen-containingby-products comprise atomic hydrogen, hydrogen ions, hydrogen radicalsor combinations thereof.

In one example, during processing, after the substrate is placed in thesubstrate processing system 232, the precursor may be supplied to theprocessing volume 226, via the showerhead 220, from the gas panel 230.This may include supplying a silicon-containing precursor (e.g., silane,dimethylsilane, trimethylsilane, tetramethylsilane, diethylsilane,tetramethylorthosilicate (TMOS), tetraethyl-orthosilicate (TEOS),octamethyltetrasiloxane (OMTS), octamethylcyclotetrasiloxane (OMCTS),tetramethylcyclotetrasiloxane (TOMCATS), mixtures thereof, etc.), andother process gases to the processing volume 226. In cases where asilicon oxide (SiOx) material is to be formed, an oxidizing gas andwater vapor may also pass through the showerhead and into the processingvolume 226. The process may also include the introduction of one or moreadditional hydroxyl-containing precursors (e.g., H₂O₂, etc.) that may bepremixed with one or more of the precursors, or separately provided tothe process chamber to form a silicon oxide (SiOx) material. In somecases, all the precursors may be premixed before being supplied as onemixture to the processing volume 226. In addition, one or more of theprecursors may be mixed with a carrier gas (e.g., an inert gas such as anoble gas (He, Ne, Ar, Kr, and Xe), nitrogen gas, etc.) before beingsupplied to the chamber.

In this deposition example, hydrogen-containing gases (e.g., atomichydrogen, hydrogen ions, hydrogen radicals, etc.) will be formed duringthe silicon oxide formation process due to the breakdown of thesilicon-containing precursors, injected water vapor, andhydroxyl-containing precursors, and thus the processes described hereincan be used to reduce the concentration of hydrogen-containing gases inthe processing volume and thus are incorporated into the deposited film.

At operation 320, the processing volume is evacuated via a vacuumforeline coupled with the processing volume.

At operation 330, a reactive gas flows into the vacuum foreline to reactwith at least a portion of the hydrogen-containing by-products. In someimplementations, the reactive gas flows into the deposition chamber andreacts with the hydrogen-containing by-products in the reaction chamber.In some implementations, gas flow between the deposition chamber and thevacuum foreline is stopped prior to flowing the reactive gas into thevacuum foreline. In some implementations, the reactive gas is anoxidizing agent, a halogen containing agent, or combinations thereof. Insome implementations, the reactive gas is an oxidizing agent selectedfrom the group of oxygen (O₂) gas, ozone (O₃), nitrous oxide (N₂O), orcombinations thereof. In some implementations, the reactive gas is NF₃.

The hydrogen-containing by-products react with the reactive gas to forma heavier by-product that can more easily pumped out by use of aconventional pumping system, such as vacuum pump 130. This heavierby-product (e.g., higher molecular mass) can be more easily pumped awayby conventional mechanical vacuum pumps (e.g., roots blower, turbo pump,etc.), ion pumps, cryopumps and getters. In some implementations, freehydrogen is reacted with an oxidizing agent in the vacuum foreline 120.

In some implementations, the reactive gas is energized prior to flowingthe reactive gas into the vacuum foreline. In some implementations, thereactive gas is energized in the vacuum foreline. In someimplementations, the reactive gas is energized both prior to flowing thereactive gas into the vacuum foreline and while in the vacuum foreline.In some implementations, the reactive gas is energized by exposing thereactive gas to at least one of an ultraviolet source, a remote RFplasma, a capacitively coupled plasma, an inductively coupled plasma, atransformer coupled plasma (TCP), a microwave, thermal energy, orcombinations thereof.

At operation 340, the reaction product of the reactive gas and thehydrogen-containing by-product are pumped out of the vacuum foreline.

Implementations of the present disclosure may be used with plasma CVDtechniques such as plasma enhanced CVD (PECVD), and high-density plasmaCVD (HDPCVD). Implementations include in-situ plasma generation in theprocess chamber (e.g., between a capacitively coupled showerhead andsubstrate pedestal/substrate), and/or remote plasma generation using aplasma generator positioned outside the process chamber. Implementationsalso include thermal CVD techniques such as atmospheric pressure CVD(APCVD), sub-atmospheric CVD (SACVD), and low-pressure CVD (LPCVD),among others.

In summary, some of the benefits of the present disclosure providesystems and methods for improved thin film deposition by reducing theamount of hydrogen present in the processing chamber and the relatedpumping system. In some of the implementations described herein, lighterhydrogen-containing by-products are converted to heavier by-products,which are removed from the system using conventional pumps.

When introducing elements of the present disclosure or exemplary aspectsor implementation(s) thereof, the articles “a,” “an,” “the” and “said”are intended to mean that there are one or more of the elements.

The terms “comprising,” “including” and “having” are intended to beinclusive and mean that there may be additional elements other than thelisted elements.

While the foregoing is directed to implementations of the presentdisclosure, other and further implementations of the present disclosuremay be devised without departing from the basic scope thereof, and thescope thereof is determined by the claims that follow.

1. A system for processing a substrate, comprising: a depositionchamber; a vacuum foreline that connects a vacuum pump to the depositionchamber; a reaction chamber fluidly coupled with and positioned alongthe vacuum foreline in between the vacuum pump and the depositionchamber; a valve to control flow between the deposition chamber and thevacuum foreline; and a reactive gas supply system, comprising: at leastone reactive gas source; an inlet line that fluidly couples the at leastone reactive gas source to the vacuum foreline; and at least one valveconnected to the inlet line to control the flow of a reactive gas fromthe at least one reactive gas source into the vacuum foreline.
 2. Thesystem of claim 1, further comprising an energy source coupled with thevacuum foreline.
 3. The system of claim 1, wherein the at least onereactive gas source is selected from an oxygen (O₂) gas source, an ozone(O₃) gas source, a nitrous oxide (N₂O) gas source, a nitrogentrifluoride (NF₃) source, or a combination thereof.
 4. The system ofclaim 1, wherein the deposition chamber is a vacuum-assisted depositionchamber.
 5. The system of claim 1, further comprising an energy sourcecoupled with the inlet line.
 6. The system of claim 1, furthercomprising an energy source coupled with the deposition chamber.
 7. Thesystem of claim 1, wherein the inlet line and the vacuum foreline joinat a location on the vacuum foreline that is upstream of the vacuumpump.
 8. The system of claim 1, further comprising an energy sourcecoupled with the reaction chamber.
 9. The system of claim 8, wherein theenergy source is selected from a UV source, a remote RF plasma source, acapacitively coupled plasma source, an inductively coupled plasmasource, a transformer coupled plasma source, a microwave source, athermal energy source, or a combination thereof.
 10. A system forprocessing a substrate, comprising: a deposition chamber, comprising achamber exhaust; a vacuum foreline that connects a vacuum pump to thedeposition chamber; a plasma source comprising a plasma source exhaustand positioned directly in-line with the vacuum foreline; an exhaustconduit coupling the plasma source to a pump; and a reactive gas supplysystem, comprising: at least one reactive gas source; an inlet line thatfluidly couples the at least one reactive gas source to either thevacuum foreline or the plasma source; and at least one valve connectedto the inlet line to control the flow of a reactive gas from the atleast one reactive gas source into the vacuum foreline.
 11. The systemof claim 10, wherein the plasma source is selected from a remote RFplasma source, a capacitively coupled plasma source, an inductivelycoupled plasma source, a transformer coupled plasma source, or acombination thereof.
 12. The system of claim 10, wherein the at leastone reactive gas source is selected from an oxygen (O₂) gas source, anozone (O₃) gas source, a nitrous oxide (N₂O) gas source, a nitrogentrifluoride (NF₃) source, or a combination thereof.
 13. The system ofclaim 1, wherein the deposition chamber is a vacuum-assisted depositionchamber.
 14. A method, comprising: flowing one or more process gasescomprising a silicon-containing gas into a processing volume of adeposition chamber; depositing a silicon oxide layer on a substratedisposed in the processing volume, wherein a gaseous hydrogen-containingby-product is formed from the one or more process gases within theprocessing volume during depositing the silicon oxide layer; flowing areactive gas into a vacuum foreline coupled with the processing volume,wherein the vacuum foreline contains the gaseous hydrogen-containingby-product and the reactive gas is selected from the group of oxygen(O₂) gas, ozone (O₃), nitrous oxide (N₂O), nitrogen trifluoride (NF₃),or a combination thereof; reacting the reactive gas with at least aportion of the gaseous hydrogen-containing by-product in the vacuumforeline to form a gaseous reaction product, wherein the gaseousreaction product contains a molecule that has a molecular mass greaterthan a molecular mass of the gaseous hydrogen-containing by-product; andpumping the gaseous reaction product out of the vacuum foreline.
 15. Themethod of claim 14, wherein the one or more process gases furthercomprises an oxidizing gas.
 16. The method of claim 14, wherein thehydrogen-containing by-products comprise atomic hydrogen, hydrogen ions,hydrogen radicals, or a combination thereof.
 17. The method of claim 14,wherein the silicon-containing gas is selected from silane,dimethylsilane, trimethylsilane, tetramethylsilane, diethylsilane,tetramethylorthosilicate (TMOS), tetraethyl-orthosilicate (TEOS),octamethyltetrasiloxane (OMTS), octamethylcyclotetrasiloxane (OMCTS),tetramethylcyclotetrasiloxane (TOMCATS), or a combination thereof. 18.The method of claim 14, further comprising energizing the reactive gasprior to flowing the reactive gas into the vacuum foreline.
 19. Themethod of claim 14, further comprising energizing the reactive gas inthe vacuum foreline.
 20. The method of claim 19, wherein energizing thereactive gas comprises exposing the oxidizing agent gas to at least oneof an ultraviolet source, a remote RF plasma, a capacitively coupledplasma, an inductively coupled plasma, a transformer coupled plasma, amicrowave, thermal energy, or a combination thereof.